[转载]代码生成技术--CodeDom VS T4

namespace RazorDemo
{
public class CodedomDemo
{
public CodeCompileUnit CrateCodeCompileUnit()
{
var testClass = new CodeTypeDeclaration(“Test“);
var testMeth = new CodeMemberMethod()
{
Attributes = MemberAttributes.Public| MemberAttributes.Final,
Name = “SayHello“,
};
var param = new CodeParameterDeclarationExpression(new CodeTypeReference(typeof(string)), “name“);
testMeth.Parameters.Add(param);
testClass.Members.Add(testMeth);

var nowExpression = new CodePropertyReferenceExpression(new CodePropertyReferenceExpression(new CodeTypeReferenceExpression(typeof(DateTime)), “Now“), “Hour“);
var assmon = new CodeBinaryOperatorExpression(new CodePrimitiveExpression(“早上好:“), CodeBinaryOperatorType.Add, new CodeArgumentReferenceExpression(“name“) );
var asslunch = new CodeBinaryOperatorExpression(new CodePrimitiveExpression(“中午好:“), CodeBinaryOperatorType.Add, new CodeArgumentReferenceExpression(“name“));
var assAfternoon = new CodeBinaryOperatorExpression(new CodePrimitiveExpression(“下午好:“), CodeBinaryOperatorType.Add, new CodeArgumentReferenceExpression(“name“));
var codecondition = new CodeConditionStatement(new CodeBinaryOperatorExpression(
nowExpression, CodeBinaryOperatorType.LessThanOrEqual, new CodePrimitiveExpression(10)),
new CodeStatement[] { new CodeExpressionStatement(new CodeMethodInvokeExpression(new CodeTypeReferenceExpression(typeof(Console)), “WriteLine“, assmon)) }, //true:if(DateTime.Now<=10)
//else
new CodeStatement[]
{
new CodeConditionStatement(new CodeBinaryOperatorExpression(nowExpression, CodeBinaryOperatorType.LessThanOrEqual,new CodePrimitiveExpression(14) ), // else if(DateTime.Now<=14)
new CodeStatement[] { new CodeExpressionStatement(new CodeMethodInvokeExpression(new CodeTypeReferenceExpression(typeof(Console)), “WriteLine“,asslunch))}, //true
new CodeStatement[] { new CodeExpressionStatement(new CodeMethodInvokeExpression(new CodeTypeReferenceExpression(typeof(Console)), “WriteLine“,assAfternoon))}) //fasle
}
);

testMeth.Statements.AddRange(new CodeStatement[] {
codecondition
});

var ns = new CodeNamespace(“Wolf“);
ns.Imports.Add(new CodeNamespaceImport(“System“));
ns.Types.Add(testClass);
var util = new CodeCompileUnit();
util.Namespaces.Add(ns);
return util;
}

public string Genertor(string language)
{
StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
System.CodeDom.Compiler.CodeDomProvider.CreateProvider(language).GenerateCodeFromCompileUnit(
this.CrateCodeCompileUnit(), sw, new System.CodeDom.Compiler.CodeGeneratorOptions()
{
ElSEOnClosing = true,
IndentString = “ “
});
sw.Close();
return sb.ToString();

}
}
}

using System;
namespace WolfT4 {
public class Test {

public void SayHello(string name) {
<# if(System.DateTime.Now.Hour<=10){#>
System.Console.WriteLine((“早上好:“ + name));
<#} else if(System.DateTime.Now.Hour<=14){#>
System.Console.WriteLine((“中午好:“ + name));
<#} else{ #>
System.Console.WriteLine((“下午好:“ + name));
<#}#>
}
}
}